Replace the third element of all sublists with another list

I have a list of lists and I want to replace/update the third element of all the sublists with a new list.

lst1 = [['a','b','c', 3],['d','e','f', 9],['g','h','i', 'j']]            
lst2 = [2, 3, 4]

Desired output:

lst_new = [['a','b', 2, 3],['d','e', 3, 9],['g','h', 4, 'j']] 

Answer

Try this:

lst1 = [['a','b','c', 3],['d','e','f', 9],['g','h','i', 'j']]            
lst2 = [2, 3, 4]

for x,y in zip(lst1,lst2): #loops over both lst1 and lst2
    x[2] = y

output:

[['a', 'b', 2, 3], ['d', 'e', 3, 9], ['g', 'h', 4, 'j']]